Trials of lipid lowering agents have not demonstrated reductions in total mortality in treatment groups; reductions in fatal CHD are offset by non- cardiac deaths, particularly traumatic deaths. Meta-analyses suggest an excess of injury mortality associated with treatment of hypercholesterolemia. The proposed nested case-control study will examine the relationships among use of lipid lowering medication and injury. The study population will consist of Group Health Cooperative (GHC) enrollees with at least one total cholesterol measurement at or above 200 mg/dL during 1986-1992. Approximately 325 injury cases and 325 non-injured controls will be identified. Injuries of interest include motor vehicle accidents, suicide or attempted suicides, and homicide assaults occurring after the date of the first elevated cholesterol test. Cases will be identified using GHC computerized hospitalization files and death tapes; case and control status will be confirmed by medical record review. Exposure to lipid lowering agents will be assessed using the GHC pharmacy database; lipid levels will be assessed from GHC automated laboratory data. Potential confounders and effect modifiers will be identified from discharge diagnoses, pharmacy databases, and medical record review. After identification of effect modifiers and adjustment for confounding, analyses will specify the relationship between current use of lipid lowering medications and injury. Further analyses will examine the relationships between injury and specific classes of lipid lowering medication, lipid lowering per se, recent changes in therapy, and differences by age, gender, and psychiatric conditions. The proposed study will also examine the utility of large HMO databases for the post- marketing surveillance of adverse drug effects.